Mars lies about 1.5 times farther from the Sun than the Earth. When it's orbit takes it on the other side of the Sun from us, it will be a tiny dot about the size of Polaris. However, we are closest to Mars when we are overtaking it in its orbit (when the Earth is directly between the Sun and Mars). At this time, called opposition, Mars will appear as a reddish or golden disk. This is the best time to observe Mars, but oppositions happen only every 2 years, so time your observing carefully.
Mars follows the same path in the sky as does the Moon (and Sun), so you would look for Mars in the constellations of the ecliptic, as this path is called. These constellations are familiarly known as the zodiac (Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius, Pisces and, unofficially, Ophiuchus). The chart tells what general direction to look.
During opposition, Mars will be a bright but tiny orange or golden disk. At opposition, it will be completely round. At other times it may appear gibbous (not quite fully round), just as Venus and our Moon do. Even at high power, the Martian disk will be small and you will have difficulty seeing surface detail. However, you should be able to make out a white glare coming from one of the polar ice caps. If you are observing at opposition, the sky is good, and you are patient, you may be able to see dark patches on the planet's surface. The most distinctive of these is a large dark triangle which looks a bit like a map of India. This area is called Syrtis Major. If you wish to see surface features, you may have to observe Mars for as much as half an hour, to wait for brief moments when the air is particularly steady and you catch fleeting glimpses. Try using a red filter to observe surface features, or a blue one to look for clouds.
Mars' inviting orange color is deceiving -- it's a cold and lifeless world, with temperatures like Antarctica. Although Mars is only half as wide as the Earth, it has about as much land mass to explore (though no oceans). A vacationer to Mars could see mammoth volcanoes. The largest one, Olympus Mons, is three times higher than Mt. Everest and could cover the country of Poland. An energetic hiker might want to explore Valles Marineris, Mar's huge Grand Canyon, which stretches nearly 3000 miles. Mars' tiny atmosphere is sufficient enough to generate both wispy clouds and great windstorms which stir up Martian dust and send it billowing around the planet at hundreds of miles an hour. From ancient river channels, we can tell there was once water on Mars, but what remains now is frozen underground or mixed with frozen carbon dioxide in the polar ice caps. Searches for life by the Viking spacecraft found nothing, although it is possible that future missions might find fossilized forms of tiny cellular organisms from the period when Mars had water. Other missions to Mars are being planned, and it is likely that Mars will be the first other planet visited, and perhaps even colonized, by humans.
Sketch Mars (at opposition, if possible. Look for the polar cap and dark patches. Record the date.
Approximate position of Mars in the early evening hours:
When Where to look Opposition*
(best time to look)
Spring 1996 not visible
Summer 1996 early AM
Fall 1996 early AM
Winter 1997 early AM
Spring 1997 east March
Summer 1997 low south
Fall 1997 south
Winter 1998 west
Spring 1998 not visible
Summer 1998 early AM
Fall 1998 early AM
Winter 1999 early AM
Spring 1999 east May
Summer 1999 low south
Fall 1999 south
Winter 2000 west
Spring 2000 low west
Summer 2000 not visible
Fall 2000 early AM
* Although Mars can be visible for several seasons at a time, it is at its best within a month or two of "opposition", when it is in the direction opposite the Sun and relatively close to Earth.
Back to the Palomares Astronomy Homepage